Cooling system



June 22, 1965 E, J, FALK 3,190,272

COOLING SYSTEM Filed April 26, 1963 such as brake or clutch mechanisms.

United States Patent O 3,190,272 COGLING SYSTEM Edward J. Falk, St. Louis, Mo., assignor to Wagner Electric Corporation, St. Louis, Mo., a corporation of Delaware Filed Apr. 26, 1963, Ser. No. 276,052 Claims. (Cl. 12S-41.09)

This invention relates generally to cooling systems and, more particularly, to a vehicle cooling system including both friction device and engine cooling branches.

In the past, separate and independent cooling systems have been provided for the engine and friction devices,

In cooling systems for forced circulation of coolant to the several brake devices of a vehicle and through a heat exchanger lfor effective dissipation of heat of friction resulting from kbrake applications, resistance of the conduits to coolant flow has a tendency to reduce the capacity and eiliciency kof pumping means and produce cavitation therein. An-

other problem prevalent in the past has been the large volume of coolant required for operating separate systems, as well as the requirement for a large volume heat exchanger. Still lanother problem has been the tendency to lose coolant due to vaporization within the engine or friction devices when operating under heavy load conditions thereby increasing the volume of coolant and causing overflow.

`in which the brake cooling branch is adapted to operate independently of the engine cooling branch to maintain the integrity of the brake devices at all times.

Another object is to obviate cavitation in the brake system pumping means and provide more eillcient operation thereof by supercharging such pumping means with lluid from the engine cooling system.

Still another object of the invention is to provide an kintegrated cooling system for a vehicle engine and friction devices using the same coolant thereby requiring a smaller total volume of coolant and a smaller total volumetric ilow rate than in separate and independent cooling systems of a vehicle.

Av further object is to provide a two branch cooling Asystem for a vehicle in which each branch can operate independently in the event of failure of the other branch. Another object is to provide a vehicle cooling system having means for accommodating volumetric variations of the coolant.

A still further object of this invention is to provide a cooling system having serially connected engine cooling means, friction device cooling means and reservoir means and in rwhich separate pumping means augment each other.

These and other objects and advantages will become apparent hereinafter.

The present invention comprises a cooling system including engine and friction device cooling systems, reservoir means having an outlet and an inlet with the engine and friction device cooling systems connected therebetween, pumping means between the engine and friction device systems and having an inlet also connected "to the outlet of the reservoir means.

y The invention also consists in the parts and in the combinations and arrangements of parts hereinafter described and claimed, with reference to the accompanying drawings in which like numerals refer to like parts:

FIGURE 1 is a diagrammatic view illustrating a pre- ICE ferred cooling system embodying the present invention, and

FIGURE 2 is a diagrammatic View illustrating a modified cooling system.

Referring now to FIGURE 1 in detail, the cooling system includes an engine cooling branch or system 10 and a friction device cooling branch or system 11, together with reservoir means including a heat exchanger 12 and an auxiliary or reserve surge tank 13.

The reservoir means has a warm fluid inlet side (also referred to as the hot side) which is shown as the upper portion 14 of the heat exchanger 12 and which receives heated or hot coolant from both branches 10 and 11 of the cooling system through a return conduit 15. The coolant passes through the heat exchanger, which may be an air cooled tube and tin radiator orthe like, and heat is thus dissipated from the coolant. The reservoir means also has a cool fluid outlet side (also referred to as the cold side) including the lower portion 16 of the heat exchanger 12 and the lower portion 17 of the surge tank 13, which are connected by a conduit 18.

It will be noted that the surge tank 13 is mounted above the level of the heat exchanger 12 and provides a supply of cooled fluid in its lower portion 17 for immediate use by the friction device cooling branch 11. The surge tank 13 also provides an upper expansion chamber 19 which is connected by a vent line 20 to the top of the heat exchanger 12 and thus provides a passage for air to escape from the heat exchanger 12 to the surge tank 13 and accommodates variations in the volume of coolant in the cooling system. The surge tank 13 has a filler cap 21 through which the system may be replenished with cooling fluid from time to time and, although the system may be vented to atmosphere through the cap 21,

it is preferred to provide a pressurized system. Therefore, although the heat exchanger 12 is shown with a filler cap 22, it is preferably a pressure cap to maintain a iluid tight seal.

The engine cooling branch 10 includes an engine 25 having an inlet 26 and an outlet 27 with the usual lluid passages through a cooling jacket therebetween for circulation of cooling fluid through the engine. An engine coolant pump 28 has a suction side 29 connected by a conduit 30 t-o the cold side 16 of the reservoir means 12 and a pressure side 31 connected to the engine inlet 26. The engine outlet 27 is provided with a thermostat 32 to control the circulation of the cooling fluid from the engine outl-et into conduits 33 or 34. The conduit 33 is a by-pass or fluid recirculation means between the engine -foutlet 2'7 and the suction side 29 of the engine pump 28 through which coolant is recirculated in a short circuit to the engine 25 when the engine is below a predetermined temperature (normally about F.) and the thermostat 32 remain closed. The thermostat 32 opens when the temperature of the coolant at the engine outlet 27 reaches the predetermined temperature and normally remains open during continued engine operation to discharge the coolant into conduit 34 connecting the engine cooling branch 10 with the friction device cooling branch 11.

The friction device cooling system 11 includes a fluid impelling or pumping means 37, preferably a positive displacement pump, having a suction side 33 connected by a conduit 39 to the conduit 34 from the' engine outlet 27. The pump 37 has a pressure side 40 connected by a conduit 41 to the inlet 42 of Va cooling fluid passage 43 of a friction device 44 (or a plurality of such devices). The friction device 44 may be a uid cooled disc brake of the type more fully disclosed in Gold et al. Patent No. 3,044,582 for Brake System. The cooling fluid passage 43 also has an outlet 45 connected by the conduit 15 vtem 11 to the heat exchanger 12 and through conduit 18 Vto the surge tank 13. Y l f Y with the hot side 14 of the reservoir means 12. The friction device 'cooling system 11 also includes a fluid supply conduit 46 connected between the cold side 17 of the reservoir means 13 and the conduits 34, 39 to thesuction `side 38 of the pump 37.

Both the engine pump 28 and the pumping means 37 may be driven by the engine l25 and lindependent drive meansV (not shown) may be provided therefor as a safety factor'in case of fan belt failure.v The engine pump k23 -is adapted to circulate a4 small volume Iof coolant at aV high rate of vHow to remove engine heat,andy it will be apparent Lthat the co-olantdischarged from'the engine 25 I through the thermostat 32 and conduit 34 will be heated atleast to the pr-edetermined'temperaturerequired to `open the thermostat -32 and therefore will be relatively hot.

However, the pumping means 37 is adapted to circulate av relatively large volume of coolant at` a'high rate ofV ll-ow and, consequently, will draw alarge volume -of coolant from the .coldside of the reservoir'means through the con- Y duit 456 relative tothe small volume ofghot fluidvdel'ivlered into the ysuction conduit YV39 from the engine 25.` Accordingly, Athe total volume of fluid circulated through vthe pumping means 37 to the friction device system 11r has a temperature that is not appreciably higher than the coolant temperature at the cold side of the reservoir means. In the operation of the cooling system, when Vthe engine f 25,is cold, the engine coolant pump 28-draws fluid from the cold side A16of the heat 'exchanger 12 through the Yconduit 30Tand `circulatesvit through-the engine inlet 26 andthe engine cooling ljacket to the engine outlet 27. The

'engine vthermostat 32 is normally closedrand causes theV fluid to be circulated through the by-pass conduit'33 back to the suction side 29 of the pump 28 and recirculated through the engine coolingV system 10 until the engine 25 reaches its operating temperature. `When this Vvpredetermined temperature is reached, the thermostat 32 coolant is then discharged from the system 11 through the Vconduit 15 to the heat exchanger 12 to'be cooled,-and will K flow through the conduit18 to the surge tank `13.

During normal Ioperation when both the engine coolant pump 28 and the brake coolantpump 37 .are functioning vwith the engine thermostat Vcontrol valve'32 open, the

pumps augment each other. The engine pump 28'draws its volumetric fluid requirement from `the heat exchanger reservoir 12, and the brake pump 37 easily accommodates through the conduit 46'.

through the` conduit`s`34 and 46.

If for some reason ,the brake coolant pump 37 is not Y functioning, the engine coolant pump 28 is provided 'a free fluid circulating path through' conduits 34 and 46 to the surge tank 13 from which coolant flows through the conduit 18 back to the heat exchanger 12 as indicated by the broken arrows. The volume of reserve uid in the surge tank 13 assures a cooled iluidsupply to the engine pump 28. .Y

f Referring now to FIGURE 2 inwhich a modified system embodying the present 'invention is shown, it will be seen that the surge tank 13 togetherv with the conduits 18 v Vand 46 are `eliminated anda conduit45 is-connected Vbetween thecold side 160i the reservoir'means -12 and the suction side 3S of the pumping means 37.V However,

,the conduit 46 isV connected above the conduit 30a predetermined distance 'to provide forcooleduid discharge to the engine pump 28 in theevent of failure ofthe pump 37.

This modification can be used only iftheheat exchanger 12is sufficiently largev toaccommodate the large volume V offli`1id-necessary toadequately cool the friction device 44gor1if aheader (not shown) yis provided at the upper portion 14 of the heat exchangerA 12.v When the engine 25 VVis below its `operating temperature, afree path for cooling `lluid from the Vreservoir rmeans 12v to the brake cooling system .'11 is provided'through vconduits 46 and 39V to the lpump 37 vwhich forcesV liuid through the friction devicev44 and return conduit 15 back to the `reservoirmeans 12. o .Y i, .Y Ifboth pumps are functioning normally and they engine 15'has reached its operating temperature toopen the thermostat 32a small volume of lluidfrom theY reservoir ymeans 12 is forcedrby theengine pump 28 through theen- ,gine 25 to the conduit 34 where 'it is joined by a larger volume of cooledfluid drawn from the heat exchanger 12 This uid is then circulatedl in the system 11 and reservoir heat exchanger as `previously f described.

In the event thegbrake coolant pump 37 is not functioning, coolant flows from the heat exchanger 12through the conduit 30 to the engine pump 28 and is forced through the engine ,25 and returnedY Vto thel heat exchanger 12 Thus, it is apparent that anovel vehicle cooling system has been Yprovided whereinbrake ,cooling and enginecoolmay be generated Vby-frictional braking. applications. The

ing'branches are interrelated [to provide improvements `meeting theobjects and advantages hereinbefore set out.

.This invention is intended to cover all changes land modifications inthe disclosure that will-be apparent to one skilled in the lart,and the invention is limited only by the scope of the claims which follow.

What I claimis: l

1. A VVcooling system including .a fluid cooledffriction brake or 'clutch device system and an engine cooling sys tem, reservoir meansjfor. cooling and storing liuid and havthis volume offluid discharged thereto from the engine Y25 and makes up its total Vvolumetric fluid requirement.

from the :surge tank reservoir 13. Accordingly, neither f pump can starve theV other, and the two pumping units function together to enable the systemftooperate con tinuously on a solid stream of coolant, the pump 28'charging the pump 37 Y and preventing cavitation and flashing. Furthermore, the pump arrangement maintains a more uniform pressurized-flow of fluidvthrough the branches 10' and 11 andthe reservoir means v12andv 13 to provide `a more uniform engine temperature. Normalfluid flow is indicated by the solid arrows in FIGURE 1.v

In the event a brakingy application is required ybefore the engine 25 reaches its normal operating temperature to open' the thermostat 32,` it Tis apparent that the pump 37 will draw its entire volumetric requirement from-the surge tank 13 through the conduits 46.and 39 and this coolant will befcircul'at'ed through the friction device cooling sysing a warmuid inlet side connected to said friction device systeml and arcool uid'outlet side, pumping means connected between the outlet side of Asaid reservoir means and said friction device system for continuously circulating cooling fluid therethrough 4for return Vto `said reservoir means, and'other means forcirculating cooling fluid from the outlet sideV of saidv reservoir means throughsaid engine cooling system and discharging itto said pumping means.

7 2. The cooling system according -to vclaim, 1 ,in which said reservoir means comprises a heat exchanger and said pumping means and othermeans having separate ycon- `Afnectionsto the outlet side of lsaid heat exchanger. v3,k The cooling system according to claim 1 rin vwhich lsaid -reservoirimeans comprises a heat exchangerVK and 'a surge ftank,.the 'surge tank being connected to and-forming a portion of outlet side of said heat exchangerfor auxiliary storagenofcooling fluid.

,4. The cooling system according to claim 3 wherein said vpumping means has a suctionside'connected to said surge tank, and said other means is connected `directly to ysaid heat exchanger. V

5. A vehicle cooling system comprising a friction brake or clutch device cooling branch and an engine cooling branch, reservoir means for receiving and cooling fluid from both branches and providing a supply of cooled fluid to both branches, said engine cooling branch having pumping means producing a relatively small volumetric uid ow therein, and -said friction device cooling branch having pumping means receiving said fluid flow from said engine cooling branch and also drawing a relatively larger volumetric fluid flow of cooled fluid from said reservoir means for circulation of the total volume of uid through said friction device cooling branch and return to said reservoir means.

6. A cooling system comprising a friction brake or clutch device cooling branch and an engine cooling branch, reservoir means including a heat exchanger -having a warm Huid inlet side, a reserve reservoir connected to the outlet of said heat exchanger and together therewith forming a cold fluid side of said reservoir means, means serially connecting said engine cooling branch and friction device cooling branch between said outlet of said heat exchanger and the inlet side thereof for circulation of a relatively low volume of fluid at a high flow rate through said engine cooling branch, and other means between said branches and connected to said reserve reservoir for circulation of a relatively high volume of uid at a high flow rate through said friction device cooling branch.

7. The cooling system according to claim 6 in which said other means is adapted to circulate cooling fluid through said friction device cooling branch independently of said engine cooling branch.

S. The cooling system according to claim 6 in which said reserve reservoir comprises a surge tank disposed horizontally above said heat exchanger, the heat exchanger outlet being at the bottom thereof and being connected to the lower portion of said surge tank, and the upper portions of said surge tank and heat. exchanger being connected by a vent line to maintain said heat exchanger full of cooling iluid and bleed air from said cooling system to said surge tank.

9. A Vehicle cooling system comprising a friction brake or clutch device cooling branch and an engine cooling branch, a heat exchanger and a surge tank forming reser- Voir means for coolant, first pumping means including a suction side and a pressure side for circuating coolant from said heat exchanger through said engine cooling branch, second pumping means including a suction side and a pressure side for circulating said uid from said engine cooling branch and from said surge tank through said friction device cooling system and to said heat exchanger.

10. The cooling system according to claim 9 wherein said engine cooling system includes thermostatic means for controlling the discharge of cooling fluid therefrom, and a by-pass conduit connected across said engine cooling system and with the suction side of said engine pumping means for recirculation of fluid through said engine cooling system when said engine is below a predetermined operating temperature.

References Cited by the Examiner UNITED STATES PATENTS 2,541,227 2/51 Findley 12S-142.5 2,748,900 6/56 Booth 12S-142.5 2,930,456 3/60 Sanford 18S-264.25 3,024,876 3/ 62 Montgomery 18S-264.2 3,047,104 7/ 62 Schjoln 18S- 264.2 3,080,857 3/63 Middendorf 12S-41.1

RICHARD B. WLKINSON, Primary Examiner.

KARL J'. ALBRECHT, Examiner. 

1. A COOLING SYSTEM INCLUDING A FLUID COOLED FRICTION BRAKE OR CLUTCH DEVICE SYSTEM AND AN ENGINE COOLING SYSTEM, RESERVOIR MEANS FOR COOLING AND STORING FLUID AND HAVING A WARM FLUID INLET SIDE CONNECTED TO SAID FRICTION DEVICE SYSTEM AND A COOL FLUID OUTLET SIDE, PUMPING MEANS CONNECTED BETWEEN THE OUTLET SIDE OF SAID RESERVOIR MEANS AND SAID FRICTION DEVICE SYSTEM FOR CONTINUOUSLY CIRCULATING COOLING FLUID THERETHROUGH FOR RETURN TO SAID RESERVOIR MEANS, AND OTHER MEANS FOR CIRCULATING COOLING FLUID FROM THE OUTLET SIDE OF SAID RESERVOIR MEANS THROUGH SAID ENGINE COOLING SYSTEM AND DISCHARGING IT TO SAID PUMING MEANS. 